Magnetic Effects Of Current Question 443
Question: A conducting ring of mass 2kg and radius 0.5 m is placed ring on a smooth horizonatal plane. The ring carries a current of i $ i=4A $ . A horizontal magnetic field B = 10 T is switched on at time t = 0 as shown in fig. The initial angular acceleration of the ring will be
Options:
A) $ 40,\pi ,rad,{{s}^{-2}} $
B) $ 20,\pi ,rad,{{s}^{-2}} $
C) $ 5,\pi ,rad,{{s}^{-2}} $
D) $ 15,\pi ,rad,{{s}^{-2}} $
Show Answer
Answer:
Correct Answer: A
Solution:
[a] Due to torque of magnetic field, ring will rotate about vertical diameter. $ \tau =I\alpha \Rightarrow MB=I\alpha $
$ \Rightarrow i\pi r^{2}B=\frac{1}{2}mr^{2}\alpha $
$ \Rightarrow \alpha =\frac{2iB\pi }{m}=\frac{2\times 4\times 10\pi }{2}=40\pi ,rad,{{s}^{-2}} $
BETA
